The homogeneous alkaline-catalyzed transesterification reaction of triacylglycerols with methanol is the chemical conversion option that has met with the greatest favor in industrial biodiesel production plants. Two liquid immiscibility phases coexist at chemical equilibrium. i.e., a biodiesel-rich upper phase and a glycerol-rich lower phase. The analytical methods proposed here enable triacylglycerols, diacylglycerols, monoacylglycerols. esters, methanol, and glycerol involved in transesterification of edible vegetable sunflower oil, m both phases that appear at chemical equilibrium, to be quantified. The procedure uses both reversed-phase liquid chromatography, in isocratic and gradient elution, and limited analytical tools. Calibration Curves were obtained for experimental purposes and highlight how the UV detector's response for the compounds based on unsaturated fatty acids varies depending on their degree of unsaturation. Finally, an experimental case is considered using the procedures described and the results show that they can identify and quantify not only the chemical species but also the main compounds in each chemical species.